Thursday, 16 February 2012

Young or old: who can stay awake better at the wheel?

Following on from my blog post last week, I looked at other research on driving being published by researchers at Loughborough University. Their second paper this year has looked at who could cope better with boring afternoon driving after a bad night's sleep, old men or young men [1]

I realize this is going to be a controversial topic, comparing driving abilities of old and young men, and the results may (or may not) be surprising. The aim of the researchers is to improve information given to drivers, and not (that I am aware of) to influence insurance companies.

Why do this study on male drivers? In the UK 90% of sleep-related accidents involve male drivers. Most afternoon sleep-related accidents involve older drivers, are they more prone to fall asleep at this time of day and therefore need specific advice to avoid these accidents?

Men from two age categories were selected; young 20-26 years old, and old 52-74 years old. All were experienced drivers, driving for more than 3 hours each week for at least the past 2 years. The drivers came in to the lab twice: after a normal night's sleep, and two weeks apart after a restricted to 5 hours sleep.

Drivers drove for a montonous 2 hours in a simulator like the one above (C) Alan in Belfast

This time they all had a light lunch before starting their 2 hour monotonous drive in the simulator. Drivers stayed in the left hand lane, at a steady speed, occasionally overtaking. Whenever the driver drove onto the "rumble strip" on the hard shoulder an "incident" was recorded. EEG (brain activity) and eye movement were monitored to determine when this lack of concentration was due to sleep, as opposed to being distracted. Drivers themselves were also monitoring how sleepy they felt.

The results showed that in fact younger drivers were more prone to having sleep-related incidents than old men at this time of day. This becomes significant after 30 minutes of driving and remained significant for the rest of the test. Young men were also more sleepy than the older men, from both their EEG patterns and their self-reports.

Young drivers were more prone to sleep-related lane crossing than older drivers
in monotonous afternoon driving after a short night's sleep. Adapted from Filtness, 2012

So are older men in fact better at driving when tired? This conclusion would agree with many other studies done looking at night time driving in different age groups [2]. Young men have more incidents during night time simulator driving and this corresponds with the road statistics (I did lose an argument with my University professor trying to counter this, he had more data on his side).

Encouragingly, both groups were able to accurately rate their sleepiness, which correlated well with the EEG measurements. The older group were slightly better at this then the younger men, but both groups did realise they were sleepy.

So why are older men more likely to have an accident on the road in the afternoon? The data shows they are better able to cope with being sleepy. Unfortunately there are no statistics to show the percentage of different age groups on the road at different times of day, only those who are in accidents, so one possibility is there are just more older men on the roads in the afternoon.

The one flaw to this study is that using a simulator might not be as accurate as on the road, as the simulator may exaggerate any sleep related incidents, as there is no real risk to the driver. However, it would be unethical to do this test scientifically with drivers on the road.

Overall, this is an excellent study to address what is causing the sleep-related accidents on the roads. It really highlights the need for researchers to record driving effects for longer than 30 minutes. For advice on driving and when to take breaks and naps, please check out their website Awake.